Combustion apparatus



Nov. 21, 1939. B. \IALJEAN 2,180,444

COMBUSTION APPARATUS Original Filed July 23, 1934 2+ 49; (50 5/ 1 3 111* H 3 k W -32 sou 0 0 o 0 0 oak 36 35 00 a c 0 o c o o 0 U I O O V D0 9 O O: 0 Q G B 42 INVENTOR. 567V V4LJE/4/V ATTORNEY.

Patented Nov. 21, 1939 COMBUSTION APPARATUS Ben Valjean, East Lansing, Mich, assignor to Motor Wheel Corporation, Lansing, Mich., a corporation of Michigan Original application m 23, 1934'. Serial N...

Divided and this application February 25, 1937, Serial No. 127,602

SCIaims.

This invention relates to combustion apparatus of the vaporizing pot type, and more particularly to an improvement in the means for handling the secondary air in apparatus of that character. The present application is a division of my co-pending application Serial No. 736,509, filed July 23, 1934, now Patent No.- 2,073,270, granted March 9, 1937, and also relates to the subject matter disclosed in my co-pending application Serial No. 118,867 filed January 2, 1937.

The principal object of the present invention is the provision of means for introducing secondary air in such manner that the relative proportion of secondary air to primary air may be materially reduced, thus eliminating an undesirable excess of air, and thereby effecting a more eflicient combustion.

In the drawing Figure 1 is a cross-sectional view of a space heater embodying the presentinventlon; and

Figure 2 is a sectional view of the apparatus shown in Figure 1 taken on substantially the line 2--2 of Figure 1.

The space heater illustrated in Figure 1 comprises a combustion chamber III, a burner ll enclosed within a jacket 12, and supporting legs I4. The combustion chamber is shown as of cylindrical formation, having a top wall l5 and a flue outlet 16 adjacent its upper extremity. The flue outlet I6 is adapted to be connected to a chimney l1 whereby the draft of the chimney is communicated to the apparatus. An automatic draft regulator I8 is shown associated with the flue outlet 16. The combustion chamber is proa5 vided with a door 19 through which access may be had to the interior of the device.

The combustion chamber 10 and the jacket 12 are here shown as being of integral construction. The jacket I2 and combustion chamber are supported by the legs M- which are attached to the intumed lower edge of the jacket by bolts 25. A burner supporting strap 24 is-also secured to the jacket l2 and the legs 14, as clearly shown in Figure 1.

The burner l I is preferably made up of a cylindrical sheet metal side wall 26, a cast metal bottom wall 21, and a cast metal top wall 28. The top wall 28 is provided with a relatively large central opening 29. The upper and lower extremities of the cylindrical sheet metal portion 26 are preferably cast into the top wall 28 and the bottom wall 21. The burner H is in open communication with the combustion chamber Ill through the opening 29 in top wall 28.

The burner II is held in operative relation to the combustion chamber by means of a screw threaded device 30 associated with the support strap 24 and adapted to engage a depression 3| in the bottom wall of the burner. When the screw threaded device 30 is properly adjusted the top wall 28 of the burner II is pressed snugly against the shoulder 32 formed at the upper extremity'of the jacket l2 and-the lower extremity of the combustion chamber H). An asbestos ring 33 is preferably positioned'between the edge of the top wall 28 and the shoulder 32 in order to insure a satisfactory joint.

Air is supplied to the apparatus through two groups of air inlet openings. The sheet metal cylindrical side wall 26 of the burner is provided with five vertically spacedrows of primary air inlet openings 31. These openings are preferably of substantially uniform size and spacing, and as shown, extend over substantially the entire area of the side wall 26. The upper wall 28 of the burner ll projects radially outwardly beyond the side wall 26 of the burner. It is provided with a plurality of uniformly spacedapart openings 38-radially outwardly from the wall 26 and immediately adjacent the inner surface of the side wall of combustion chamber l0. As clearly illustrated in Figures 1 and 2, the primary air inlet openings 31 are relatively much more numerous than the. secondary air inlet openings 38. Consequently, the volume of air admitted to 30 the apparatus by the primary air inlet openings is substantially greater than the volume of air admitted to the apparatus by the secondary air inlet openings.

The draft communicated to the apparatus from the chimney I1 causes primary air to be admitted to the burner H in a generally horizontal direction, and causes secondary air to be admitted to the combustion chamber in a generally vertical direction. Burner supporting strap 24 does not close the bottom of jacket 12 so that the air of the atmosphere has access to the openings 31 and 3B.

Liquid fuel is supplied to the bottom of the burner chamber from a source of supply not shown through a supply pipe 4|. A conventional constant level or metering device 42 is associated with supply pipe 4| whereby the quantity of fuel delivered to the apparatus'may be regulated.

Baffle means in the form of an annular ring 49 having depending radial vanes 50 is mounted upon the top wall 28 of the burner H. Thebaflle 49 is preferably formed in two sections as illustrated, to facilitate assembly and removal thereof. A centralopening 5| is formed in the baffle i which is arranged in alignment with the opening 29 in top wall 28. The opening II in baflle ring 491s concentric with and larger than the opening 29 in top wall 28. The battle is of such size that 5 the periphery thereof is spaced a slight distance from the combustion chamber Ill. As clearly shown, the baflle 49 is arranged above and closely adjacent the secondary air inlet openings 38.

The combustion apparatus illustrated in the 10 accompanying drawing is. as previously mentioned, of the vaporizing pot type. It is an inherent characteristic of such apparatus that the vertical location of the zone of combustion in the apparatus may be varied by regulating the 15 quantity of fuel supplied to the apparatus.

The supply of liquid fuel to the burner ll through supply pipe 4| can be controlled by suitable adjustment of the metering device 42. When the fuel is first ignited. combustion initially oc- 20 curs in the lower portion of chamber H and will remain in that portion of the chamber so long as but a limited supply of fuel is admitted thereto. As the supply of fuel is increased. visible combustion (flame) rises in the chamber until 25 finally at the maximum fuel feed it is localized wholly within the combustion chamber l0. At this stage of operation all or substantially all of the air admitted through openings 31 is being premixed with the oil vapor in advance of com- 30 bustion. By suitable adjustment of the metering device 42 of the lower limit of the zone of combustion may be localized in any desired position between the bottom of the burner II and the secondary air inlet openings 38 in the combustion 35 chamber Ill.

The expression zone of combustion" is used herein to define the major portion of the flame produced in the apparatus. It should, of course, be understood that there may be intermittent 40 flashes of flame, particularly adjacent the primary air inlet openings 31, outside of what is here termed as the zone of combustion.

In addition to merely supplying air to increase the capacity of the apparatus, the secondary air 45 inlet openings 38 also serve to distribute the flame at the higher stages of operation and cause it to spread out adjacent the side wall of the combustion chamber, thus assuring an eflicient transfer of the heat generated to the medium to be heated.

In the vaporizing pot type burners of the prior art it has been thought necessary to introduce secondary air in such a concentrated volume as to definitely flx the highest point at which the lower limit of the zone of combustion may arise. This results in admitting an undesirable excess of air to the apparatus.

According to the present invention this unde- 60 sirable excess of secondary air has been eliminated, and extinguishment of the flre by reason of the generation of an excess of fuel vapors is avoided by the use of the baflle 49. The baflle is arranged with respect to the secondary air inlet 65 openings 38 whereby to substantially confine a portion of the air entering therethrough in a limited zone and to effectively prevent contact therewith of any great amount of fuel vapors. Thus, at the higher fuel feeds, there is always 7 maintained between the central opening in the baflie 49 and the central opening in top wall 23 a mixture of air and fuel vapors containing a sufficient quantity of air to support combustion. So

long as flre is maintained in the apparatus, the

75 Possibility of an explosion because of the generation of an excess of fuel vapors is eflectively eliminated.

It is by reason of the particular construction and location of the baflie 49 that it is able to accomplish the function just described. From the drawing it will be noted that the baffle is arranged above the secondary air inlet openings 38 in such manner as to intercept the flow of the air admitted therethrough, reducing its velocity and changing the direction of flow thereof. In other words the air admitted through openings 38 impinges against baflie 49. A portion of the air admitted through the secondary air inlet openings is diverted toward the center of the apparatus where at the higher stages of operation it mixes with the premixture of oil vapors and air delivered to the combustion'chamber from the burner through the opening 29 in top wall 23. It also permits a limited portion of the air admitted through secondary air inlet openings 38 to travel up the sides of the combustion chamber l0, thus efficiently distributing the flame at the higher stages of operation.

From the foregoing it will be apparent that the essential requirement for preventing extinguishment of the flame is the provision of means for producing a combustible mixture in the apparatus regardless of the amount of fuel vapors which may be generated. Of course, this mixture must be produced in a region where it will become ignited when the apparatus is operated at maximum fuel consumption. Likewise, it should be so located and of such a nature as not to impair the normal operating efficiency of the apparatus. For example, air should not be introduced for this purpose in such volume as will materially decrease the percentage of CO: in the flue gases. Nor should the air provided for this purpose be introduced in a quantity or a direction such as will adversely influence the stabil- 40 ity of the combustion process.

The scope of the invention is indicated in the appended claims.

I claim:

1. A burner of the vaporizing pot type comprising a vertically disposed tubular side wall, a centrally apertured horizontal top wall having a periphery extending beyond the side wall, means fordelivering liquid fuel to the burner in regulatable quantities to be vaporized in the burner, a plurality of primary air inlet openings formed in the side wall of the burner below the top wall, said primary air inlet openings being proportioned and arranged to introduce air to the burner for prcmixing without any substantial amount of visible combustion with fuel vapors generated in the burner at certain rates of oil flow to theburner, a plurality of secondary air inlet openings formed in the top wall and adapted to admit air to the apparatus above the top wall outwardly of the side wall, and a centrally apertured baflle ring positioned in spaced relation above the top wall over said secondary air inlet openings, said baflle ring being constructed and arranged to present an obstruction against which the air admitted through said secondary air inlet openings impinges, said bailie having a central opening larger than the aperture in the top wall and having an overall diameter less than the overall diameter of the top wall. v

2. A burner of the character defined in claim 1, wherein the said primary and secondary air inlet openings constitute the sole means for admitting air to the burner, and wherein the volume of air admitted through the secondary air inlet openings is less than one-half of the total volume of air admitted to the burner.

3. A burner of the vaporizing pot type comprising a side wall, a top Wall formed to provide an outlet opening for the burner, means for delivering liquid fuel to the burner in regulatable .quantities to be vaporized in the burner, a plurality of primary air inlet openings formed in the side wall of the burner below the top wall, said primary air inlet openings being proportioned and arranged to introduce air to the burner for premixing without any substantial amount of visible combustion with the fuel vapors generated in the burner at certain rates of oil flow to the burner, a plurality 'of secondary air inlet openings formed in a wall of the burner above the primary air inlet openings and adapted to introduce air to the apparatus above the top wall, and a baflle ring positioned in spaced relation to the top wall above the secondary air inlet openings, said baflie ring having an opening therein larger than the outlet opening in the top wall and arranged in substantial alignmen therewith, said baiile ring and said secondary air inlet openings being constructed and arranged so that the axis of said openings intersect the median horizontal plane of said bafiie ring at a substantial angle whereby the baffle presents an obstruction against which the air admitted through said secondary air inlet openings im pinges.

4. A burner of the character defined in claim 3, wherein said primary and secondary air inlet openings constitute the sole means for admitting air to the burner, and wherein the volume of air admitted through the secondary air inlet openings which impinges against the baflle is substantially less than one-half of all the air admitted to the burner.

5. A burner of the character defined in claim 3, wherein the bafiie ring is also constructed and arranged to direct at least a portion of the air admitted through the secondary air inlet openings toward the outlet opening in the top wall.

BEN VALJEAN. 

